Trophic relationships in a deep Mediterranean cold-water coral bank (Santa Maria di Leuca, Ionian Sea)

Abstract

Cold-water corals (CWC) are frequently reported from deep sites with locally accelerated currents that enhance seabed food particle supply. Moreover, zooplankton likely account for ecologically important prey items, but their contribution to CWC diet remains unquantified. We investigated the benthic food web structure of the recently discovered Santa Maria di Leuca (SML) CWC province (300 to 1100 m depth) located in the oligotrophic northern Ionian Sea. We analyzed stable isotopes (δ 13 C and δ 15 N) of the main consumers (including ubiquitous CWC species) exhibiting different feeding strategies, zooplankton, suspended particulate organic matter (POM) and sedimented organic matter (SOM). Zooplankton and POM were collected 3 m above the coral colonies in order to assess their relative contributions to CWC diet. The δ 15 N of the scleractinians Desmophyllum dianthus, Madrepora oculata and Lophelia pertusa (8 to 9 ‰) and the gorgonian Paramuricea cf. macrospina (9 to 10 ‰) were consistent with a diet mainly composed of zooplankton (6 to 7 ‰). The antipatharian Leiopathes glaberrima was more 15 N-depleted (7 to 8 ‰) than other cnidarians, suggesting a lower contribution of zooplankton to its diet. Our δ 13 C data clearly indicate that the benthic food web of SML is exclusively fuelled by carbon of phytoplanktonic origin. Nevertheless, consumers feeding at the water-sediment interface were more 13 C-enriched than consumers feeding above the bottom (i.e. living corals and their epifauna). This pattern suggests that carbon is assimilated via 2 trophic pathways: relatively fresh phytoplanktonic production for 13 C-depleted consumers and more decayed organic matter for 13 C-enriched consumers. When the δ 13 C values of consumers were corrected for the influence of lipids (which are significantly 13 C-depleted relative to other tissue components), our conclusions remained unchanged, except in the case of L. glaberrima which could assimilate a mixture of zooplankton and resuspended decayed organic matter.

First record ofProtoptilum carpenteri(Cnidaria: Octocorallia: Pennatulacea) in the Mediterranean Sea

“…Minimum, maximum, mean and standard deviation of the biometric measurements (mm) and the % of the rachis of Protoptilum carpenteri in relation to the total length of the colony in the four colonies collected close to the Santa Maria di Leuca (SML) coral province. increases the knowledge of the biodiversity of this area (Carlier et al 2009;Mastrototaro et al 2010;Vertino et al 2010). The three colonies sampled in April 2010 were found within the facies of Kophobelemnon stelliferum described in the same area by Mastrototaro et al (2013) and wrongly reported as Distichoptilum sp.…”

Macro- and megafauna recorded in the submarine Bari Canyon (southern Adriatic, Mediterranean Sea) using different tools

“…This polychaete lives in close association with the coral host, building a parchment tube between the living coral branches, and somehow stimulating the coral to produce additional exoskeletal calcification on the thin tube of the polychaete. This interaction contributes to a strengthening of the reef framework by thickening and connecting coral branches, acting as a positive feedback on the development of CWC bioconstructions, although it is still not clear whether or not this process also enhances the food relationship between corals and E. norvegica (Roberts, 2005;Carlier et al, 2009;Mueller et al, 2013). This Eunicidae is widespread on CWC reefs and its presence on the Bari Canyon CWC bio-constructions was already known, in association with both M. oculata and L. pertusa colonies (Roberts et al, 2006(Roberts et al, , 2009.…”

“…1: Uniqueness or rarity; 3: Importance for threatened, endangered or declining species and/or habitats; 5: Biological productivity; 7: Naturalness) as well as the VME (Vulnerable Marine Ecosystem) criteria (1: Uniqueness or rarity; 2: functional significance of the habitat; 3: fragility; 4: life-history traits that make recovery difficult; 5: structural complexity) (FAO, 2009) could also be assigned to the Bari Canyon in planning future marine protected areas and management measures in order to preserve its high biodiversity level in relation to the presence of cold-water coral species. Freiwald et al, 2009;Bo et al, 2012;Sanfilippo et al, 2013;Angeletti et al, 2014;D'Onghia et al, 2014; present paper; B: Tursi et al, 2004;Longo et al, 2005;Schönberg & Beuck, 2007;Carlier et al, 2009;Freiwald et al, 2009;D'Onghia et al, 2010D'Onghia et al, , 2011D'Onghia et al, , 2012Mastrototaro et al, 2010Mastrototaro et al, , 2013Mastrototaro et al, , 2014.…”

Assessment of goods and services, vulnerability, and conservation status of European seabed biotopes: a stepping stone towards ecosystem-based marine spatial management

“…Goods and Services: Deep-sea coral communities are considered as biodiversity hotspots, representing patches of high diversity in a low diversity environment (Henry & Roberts, 2007;Carlier et al, 2009;Mastrototaro et al, 2010). It is hypothesized that reefs may function as centres of spreading for associated fauna .…”